Railings formed of plastic pipe have been popular along the seashore because of the resistance of the plastic pipe to corrosive effects of the salt air. Plastic pipes may be assembled by using the normal T-fittings and elbows which are widely available. To prevent warping or misalignment of the joints and to provide additional strength, metal liners have been provided to fit within the bore of the plastic pipe and reinforcing plugs have been installed in the joints to resist separation and to provide strength to compensate for the weakness which would otherwise be present in the joints.
The usual pipe fittings for plastic pipes are not designed for aesthetics and several attempts have been made to improve the aesthetics of the railings by modifying the normal fittings. One technique is to make the fittings of an outside diameter corresponding to the outside diameter of the plastic pipe and to provide a rabbeted joint to connect the fittings to the rails. The counterboring of the ends of the rails and/or fittings to provide the rabbeted joint tends to weaken the joint and requires the use of a reinforcing element. Furthermore, the seam at the rabbeted joint can be unsightly and to improve its appearance would require a skilled operator to weld the seam so as to minimize its unsightliness.
It is not uncommon for railings to become damaged after installation and with the existing railing assemblies, the removal and replacement of a damaged rail section entails replacement of the entire section of the railing and to avoid unsightly appearances at the areas where the section has been replaced, it is frequently preferable to replace the entire assembly.